Today’s “Summer Under the Stars” on TCM salutes Peter Lorre, which means a lot of wonderful movies. Start at 7:30 a.m. ET with 1944’s riotous Arsenic and Old Lace, and make sure to be there at 8 p.m. ET with the creepy German masterpiece, 1931’s M (with Lorre playing an accused child molester, pictured), is televised. Others shown today and tonight are treats, but those two are gems.